The present invention relates to electric discharge and incandescent lamps of the type in which a light-transmitting envelope immediately surrounding the electrodes or filament, as the case may be, is arranged to operate in air, i.e. it is not sealed within an outer jacket which is evacuated or contains a non-oxidising atmosphere; such lamps will hereinafter be referred to as air-exposed lamps. In particular the invention relates to air-exposed lamps of the kind employing so-called "ribbon seals", such lamps incorporating at least one current supply foil, usually of molybdenum, embedded within and extending along a stem at an end of the envelope, the foil being connected electrically at its inner end to an inner conductor (which in the case of a discharge lamp carries or forms an electrode of the lamp and in the case of an incandescent lamp is connected to the lamp filament) and at its outer end to a conductor constituting a current supply terminal, the ends of the conductors that are connected to the foil being also embedded in the stem. One such lamp is described in U.K. Patent Specification No. 599489.